LayoutTests/fast/forms/auto-fill-button/input-auto-fill-button.html

<p>This tests that the AutoFill button renders. It can only be tested in the test tool.</p>
<div id="container">
    <input type="text">
    <input type="password">
</div>
<script>

if (window.internals) {
    var inputs = document.querySelectorAll("input");
    for (var i = 0; i < inputs.length; ++i)
        window.internals.setShowAutoFillButton(inputs[i], "AutoFillButtonTypeCredentials");

    var dynamicInput = document.createElement("input");
    window.internals.setShowAutoFillButton(dynamicInput, "AutoFillButtonTypeCredentials");
    document.querySelector("#container").appendChild(dynamicInput);

    var dynamicInput2 = document.createElement("input");
    window.internals.setShowAutoFillButton(dynamicInput2, "AutoFillButtonTypeCredentials");
    document.querySelector("#container").appendChild(dynamicInput2);
    dynamicInput2.setAttribute("type", "password");
}
</script>